1. Field of the Invention
The present invention relates to a depth control device, more particularly to a depth control device for a powered fastener driving tool. The depth control device can be easily operated to adjust the depth of penetration of a fastener into a workpiece.
2. Description of the Related Art
In U.S. Pat. No. 5,385,286, there is disclosed an adjustable depth control which includes an upper safety rod, a lower safety rod, and a coupling that couples the upper and lower safety rods together. The upper safety rod is rigidly affixed to the coupling to prohibit linear motion relative to the coupling. The bottom side of the coupling has a lower cam face that is spring-biased against a spacer, thereby preventing the coupling from rotating. The spacer is formed with an upper cam face in sliding contact with the lower cam face of the coupling. The lower safety rod is connected threadedly to the coupling.
Some disadvantages of the aforesaid adjustable depth control for a driving tool are as follows:                (1) It is relatively inconvenient to adjust the depth of a fastener into a workpiece, because the user needs to hold the lower safety rod with one hand while rotating the coupling with the other hand to move the lower safety rod relative to the coupling; and        (2) The spring for biasing the spacer against the coupling so as to prevent rotation of the coupling may suffer from spring fatigue after a long term of use so that the coupling cannot be firmly retained.        